JPH0475047A - Device for protecting shutter blind for camera - Google Patents

Abstract

PURPOSE:To prevent a shutter blind from being scratched at the time of feeding a film by making a shutter in an open state while the leading edge of the film passes just after an aperture at the time of feeding the film. CONSTITUTION:This device is provided with the shutter 26 in which the shutter blind is opened and closed just before the aperture 25 and a feeding means 21 for feeding the film FI between a cartridge 10 and a winding spool 23. At the time of feeding the film FI, shutter control means 31 and 43 make the shutter 26 in the open state at least while the leading edge of the film FI passes just after the aperture 25. Thus, the shutter curtain is prevented from being scratched by the leading edge of the film FI at the time of performing a thrust action or a rewinding action.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a shutter curtain protection device used in a camera that feeds film by rotating a spool shaft of a film cartridge.

B. Prior Art For example, the following film cartridge has been disclosed in US Pat. No. 4,832,275. This consists of a cylindrical part that houses a spool shaft around which the film is wound, and a delivery part that extends integrally in the tangential direction of this cylindrical part. It is stored in That is, when the cartridge is not loaded into a camera, no film is exposed from the cartridge.

The following cameras have been proposed that can use this type of cartridge. When a cartridge is loaded into the camera body, the spool shaft (on which the film is wound) of the cartridge is first rotated to feed the film out of the cartridge and guide it to the winding spool (this is called a thrust operation). Thereafter, the leading end of the film is wound around the winding spool inside the camera body, and the winding operation is performed in the same way as usual to make it ready for photographing. According to such a camera and cartridge, the cartridge itself is easy to handle, and mistakes in film loading are reduced.

Problems that the C1 invention attempts to solve By the way, for example, the shutter of an eye reflex camera.

This is a focal plane shutter in which the shutter curtain opens and closes just before the aperture, and when a film feeding mechanism that performs the above-mentioned thrust operation is used in a camera having such a shutter, the following problems occur. In other words, the film sent out from the cartridge passes just behind the aperture, but the leading edge of the film is usually curled due to the curling of the film when it is wound around the spool shaft of the cartridge. When the leading edge of the film passes just behind the aperture, it may catch the shutter curtain and damage it. Also, when rewinding the film, the leading edge of the film passes directly behind the aperture, so there is a risk of damaging the shutter curtain as described above.

SUMMARY OF THE INVENTION An object of the present invention is to provide a shutter curtain protection device that prevents the shutter curtain from being damaged during film feeding.

1(a) and 1(b) showing an embodiment of a means for solving the problem D1, the present invention has a shutter 26 whose shutter curtain opens and closes immediately before the aperture 25, and a film Feeding means 2 for feeding FI between the cartridge 10 and the winding spool 23
1, and is applied to a shutter curtain protection device used in a camera in which the film FI passes directly behind the aperture 23 during film feeding. Then, when feeding the film,
The above-mentioned problem is solved by providing shutter control means 31, 43 for keeping the shutter FI open at least while the leading edge of the film FI passes directly behind the aperture 25.

When feeding the film FI, the shutter control means 31.43 keeps the shutter 26 open at least while the leading edge of the film FI passes directly behind the aperture 25. This prevents the leading edge of the film FI from damaging the shutter curtain during thrust operation or rewinding operation.

F. Example An embodiment of the present invention will be described with reference to FIGS. 1 to 7.

FIG. 2 is a perspective view of a camera having a shutter curtain protection device according to the present invention, seen from the rear, and FIG. 3 is a diagram showing the inside thereof.

1 is a camera body, 2 is a photographing lens attached to the front of the camera body 1, and 3 is an eyepiece of a finder. 4 is a cartridge chamber provided in the camera body 1, 5 is a lid of this cartridge chamber 4 (hereinafter referred to as a cartridge lid), and a film cartridge 10 as shown in FIG. 1(a) is loaded in the cartridge chamber 4. be done.

FIG. 1(a) schematically shows the film drive mechanism inside the camera body, and the cartridge 1o is integrated with a cylindrical part 11 that houses a spool shaft (not shown) and a tangential direction of this cylindrical part 11. and a delivery section 12 connected to. Cylindrical part 1
1 stores the film FI wound around the spool shaft, and the leading end of the film FI is stored in the delivery section 12 in a straight state. That is, at the stage of loading the cartridge 10 into the camera body 1, the film FI is completely housed within the cartridge 10 and is not exposed to the outside, as shown in FIG.

Also, inside the camera body 1, there is a thrust and rewind motor 21, and an engagement shaft 22 driven by this motor 21.
, a film winding spool 23, and a winding spool driving motor (hereinafter referred to as a winding motor) 24 are provided, respectively. When the cartridge 10 is loaded into the cartridge chamber 4, the engagement shaft 22 is adapted to engage with the engagement portion 11,a provided at the upper part of the spool shaft.
The rotation of the engagement shaft 22 causes the spool shaft to rotate (normally or reversely). By normal rotation of the spool shaft, the film FI wound around the spool shaft is sent out (as will be explained in detail later).
A thrust operation) is performed, and rewinding is performed by reversing the spool shaft. Further, the film FI is wound up by the rotation of the winding spool 23. and film feeding (thrust, winding).

During rewinding), the film FI passes directly behind the aperture 25.

Here, 6 in Fig. 2 is a slit for passing the film, and 6 is a slit for passing the film.
In the figure, 25 is an aperture, 26 is a shutter (focal plane shutter), and the shutter curtain of the shutter 26 is opened and closed just before the aperture 25.

Further, as shown in FIG. 3, a photosensor 27 is provided at the lower right of the aperture 25 in the drawing.

The photosensor 27 includes a light emitting element and a light receiving element that receives light emitted from the light emitting element and reflected by the film FI, and the light received by the light receiving element is converted into an electrical signal and output. Therefore, if the film FI is present at the location where the photosensor 27 is located, the electrical signal will be a predetermined value or more, and if the film FI is not located, it will be less than the predetermined value.

FIG. 1(b) is a block diagram showing the control system of the above-mentioned camera, and the control circuit 31 that controls the entire sequence of the camera includes a photometry circuit 32. Film sensitivity detection circuit 332
A position detection circuit 34 and switches SWI to SW3 are connected. The photometry circuit 32 detects the brightness of the subject (subject luminance) and inputs it to the control circuit 31 . The film sensitivity detection circuit 33 detects the ISO sensitivity from a film sensitivity code (not shown) given on the cartridge 10 and inputs it to the control circuit 31. The above-mentioned photosensor 27 is connected to the 0 position detection circuit 34. The output is amplified and input to the control circuit 31.

The switch SWI is a release switch that is turned on in conjunction with a full press operation (release operation) of a release button (not shown), and the switch SW2 is a cartridge presence detection switch that detects whether or not the cartridge 1o is loaded in the cartridge chamber 4. If the cartridge 10 is loaded, it is on, and if it is not, it is off. The switch SW3 is a cartridge lid detection switch that detects the open/closed state of the cartridge lid 5, and is turned on when the cartridge lid 5 is closed and turned off when it is opened. The switch SW4 is a power switch connected to the power supply circuit 35, and is turned on by pressing the release button halfway.
supplies power to each circuit.

Further, the power supply circuit 35 similarly performs the power supply operation when the cartridge lid detection switch SW3 is turned on.

Five drivers 41 to 45 are also connected to the control circuit 31. The driver 41 drives the thrust and rewind motor 21, and the driver 42 drives the hoist motor 24.

The driver 43 drives the shutter 26, the driver 44 drives the aperture 46, and the driver 45 drives a display device 47 (for example, a liquid crystal display device, which is provided on the surface of the camera body 1).

Next, the control procedure by the control circuit 31 will be explained with reference to the flowcharts of FIGS. 4 and 5.

When the power supply circuit 35 starts supplying power by turning on the above-mentioned power switch SW4 or cartridge lid detection switch SW3, this program is started, and first, in step S1 of FIG. 4, it is determined whether or not the cartridge 10 is loaded. If the cartridge 10 presence/absence detection switch SW2 is on, it is determined that the cartridge 10 is loaded and the process proceeds to step S2, and if the switch SW2 is off, it is determined that the cartridge 10 is not loaded and the process proceeds to step S18.

In step 818, the shutter 26 is allowed to operate but the film FI is not wound (sequence 1).
)I do. The details are omitted because they are not related to the present invention.

In step S2, the loading operation of the film FI (
It is determined whether or not the thrust operation and the winding operation have already been completed and the camera is ready for photographing. If loading has not yet been performed, loading processing from step S3 onwards is performed.

Here, if loading is not completed, this means that the start of this program is when switch SW3 is turned on.

In other words, this indicates that the process was started by closing the cartridge lid 5 after loading the cartridge.

In step S3, the release is prohibited, and exposure is not activated even if the release switch SWI is turned on. Next, in step S4, the motor 21 is
, 24 to rotate the engagement shaft 22 in the counterclockwise direction (forward rotation) in FIG. 1(a) and rotate the first-winding spool 23 in the same direction. Thereafter, in step S5, the shutter 26 is opened, and the spool shaft of the cartridge IO is rotated by the forward rotation of the engagement shaft 22, as shown in FIG.
The film FI wound around this spool shaft is sent out from the delivery port at the tip of the delivery section 12 of the cartridge 10. That is, a thrust operation is started. The fed film FI passes through the slit 6 (FIG. 2), passes immediately after the aperture 25 as shown in FIG.
I am guided by 3.

Next, in step S6, the output of the position detection circuit 34 is read and it is determined whether the leading edge of the film FI has finished passing through the aperture 25 or not. If the output of the position detection circuit 34 is less than a predetermined value, it is determined that the film FI is not present at the position of the photosensor 27, that is, the leading edge of the film FI has not yet finished passing through the aperture 25, and the process proceeds to step Sll.

In step Sll, it is determined whether the film FI has been wound around the winding spool 23 by means not shown. For example, when the film FI is wound around the take-up spool 23, a load is applied to the motor and its rotation is reduced, so it may be determined that the film is wound when the rotation of the motor is less than a predetermined value. Alternatively, a photosensor may be provided on the winding spool 23 for detection.

If step Sll is negative, the process returns to step S6, and if affirmative, the process proceeds to step S12. Here, step S
If step S11 is affirmed after step 6 is negative, it means that the film FI has not passed through the aperture 25 but is wound around the winding spool 23. This seems contradictory, but in reality, for example, the film FI is dirty and the light from the light emitting element of the photosensor 27 is not reflected, so even though the film FI is wound around the winding spool 23. Position detection circuit 34
When the output of is less than a predetermined value, step Sll is affirmed. In this case, the shutter 26 is closed in step 312, and then the motor 21 is stopped in step 813 to stop the thrust operation.
Proceed to step 4.

In step S14, only the winding motor 24 is driven to start winding, and when it is determined in step S15 that winding for one frame has been completed, the motor 24 is stopped in step 816 to stop winding. That is - here the shutter 26
Since the film FI was fed until it was wound around the winding spool 23 while the film was open, the first frame was wasted, so the film FI was wound up by one frame and the film FI was fed for two frames. Start shooting from the eyes. Then, a warning is given to that effect in step S17, and the process proceeds to step SlO.
The warning is an operation of displaying the above information on the display device 47 via the driver 45.

On the other hand, if the output of the position detection circuit 34 is equal to or higher than a predetermined value in step S6, it is determined that the film FI exists at the position of the photosensor 27, that is, the leading edge of the film FI has already passed through the aperture 25. 23
), the shutter 26 is closed in step S7.
Close. Step S8 waits until it is determined that the film Fl is wound around the winding spool 23, and then the motor is stopped in step S9, and step S
At step 10, release is permitted and the process is terminated.

According to the above steps 84 to S9, the shutter 26 opens at the start of the thrust operation, and the cartridge 1
Since the shutter 26 closes after the leading edge of the film FT sent out from 0 passes through the aperture 25, the shutter 26 remains open while the leading edge of the film passes through the aperture 25, and the shutter curtain is damaged by the leading edge of the film. Moreover, since the shutter 26 is closed before the film is wound around the winding spool 23, the first frame and subsequent frames are not exposed undesirably.

On the other hand, if it is determined in step S2 that loading has been completed, the process advances to step S19 in FIG. here,
Completion of loading indicates that this program was started by turning on switch SW4, that is, by pressing the release button halfway.

In step S19 in FIG. 5, normal photographing processing is performed. The content of this normal shooting process is to first calculate the exposure value (aperture value and shutter speed) from the subject brightness input from the sub-light circuit 32 and the film ISO sensitivity input from the film sensitivity detection circuit 33, and then calculate the exposure value. Driver 44.43 according to
The diaphragm 46 and shutter 26 are driven via the aperture 46 and the shutter 26 to take a photograph. Thereafter, the winding motor 24 is driven via the driver 42, and the winding spool 23 is rotated, so that the film F
Wind up the pieces.

Next, in step S20, it is determined whether or not all the frames of the film Fl have been photographed. If the answer is negative, the process is terminated, and if the answer is affirmative, the film FI is rewound from step S21 onwards. First, in step S21, the release is prohibited, and then in step S22, the thrust and rewind motor 21 is rotated in the opposite direction to that described above via the driver 41, and the engagement shaft 22 is rotated clockwise (reversely).

This causes the spool shaft to rotate in the same direction, and the film FI
is rewound into cartridge 10.

In step S23, the output of the position detection circuit 34 is read and it is determined whether the leading edge of the film FI has passed the position of the photosensor 27 or not. If the answer is NO, the process advances to step S29 to check whether the rewinding is completed, that is, the film FI
It is determined whether or not the tape has been rewound into the cartridge 10 to the leading end. This can be done, for example, by providing a photosensor near the cartridge 10 and making the determination based on its output.

If step S29 is negative, the process returns to step S23,
If affirmative, a warning is issued on the display device 47 in step S30, and the process advances to step S27. That is, if the film FI is dirty as described above, step S29 may be affirmed after step S23 is negative, and this fact is notified.

On the other hand, if step S23 is affirmed, step S24
The shutter 26 is opened, and then in step S25, it is determined whether rewinding has been completed, as in step S29 described above. If step S25 is denied, wait until it is affirmed, and if it is affirmed, in step S26 the shutter 26 is
At the same time, the motor 21 is stopped in step S27, and the completion of rewinding is displayed on the display device 47 in step 328, and the process is ended.

According to the above steps 822 to 326, after the start of rewinding the film FI, immediately after the leading edge of the film FI passes the position of the photosensor 22, that is, the aperture 25
The shutter 26 opens just before the rewind starts, and then closes when the rewind is completed. Therefore, the shutter 26 is open while the leading edge of the film passes just behind the aperture 25, and the shutter curtain is not damaged by the leading edge of the film. Furthermore, since the first frame has already been rewound into the cartridge 10 when the shutter 26 opens, it will not be exposed undesirably.

Note that the shutter 26 may be opened as the film FI leaves the take-up spool 23.

In the configuration of the above embodiment, the thrust and rewind motor 21 serves as the feeding means, and the control circuit 31 and the driver 4
3 respectively constitute shutter control means.

FIG. 8 shows another embodiment, in which steps 84 to S7 in FIG. 4 are modified.

In FIG. 8, after the motor 21 is rotated forward to start the thrust operation in step S4, time measurement is started in step S31, and the shutter 26 is opened in step S5. Thereafter, in step S32, a predetermined time period is waited for from the start of the time measurement, and then, in step S7, the shutter 26 is closed. Here, the timer incorporated in the control circuit 31 may be used for the above-mentioned time measurement, and the predetermined time is set as the time required for the leading edge of the film F2 to completely pass through the aperture 25. With this, the shutter is open at the leap where the leading edge of the film Fl passes immediately after the aperture 25 during thrust, so the shutter curtain will not be damaged in the same way as described above. Since there is no need to use the sensor 27, costs can be reduced, and even if the film FI is dirty, there will be no effect.

Furthermore, FIG. 9 shows an embodiment in which steps 84 to s9 in FIG. 4 are modified. That is, after the motor 21 is rotated forward to start the thrust operation in step S4, the shutter 26 is opened in step S5, and the wait is continued until it is determined that the film FI is wound around the winding spool 23 in step S8. The shutter 26 is closed in step S7, and the motor 21 is stopped in step S9. This also protects the shutter curtain and eliminates the need for the photosensor 27 as described above. However, in this case, since the shutter 26 closes after the film FI has been ejected for a longer time than described above, there is a high possibility that the first frame of the film FI will be exposed. Not suitable for cameras with long distances.

FIGS. 10(a) and 10(b) show yet another embodiment. The film FI in this example has perforation PF.
A photosensor 71 (same configuration as the photosensor 27) is provided inside the camera body 1 at the upper left of the aperture 25 in the figure, that is, at a position through which the perforation PF passes during film feeding. During film transport, the output of the photosensor 71 repeats high and low levels due to the perforations PF, and by counting the number of times the perforations PF passes, the number of passes through the perforations PF, that is, the film feeding amount can be obtained.

To explain the operation of this embodiment, first, the shutter 26 is opened at the same time as the thrust starts, and the above counting is performed. When the leading edge of the film reaches the number of perforations passing through the aperture 25 (predetermined), the shutter 26 is opened.
Close 6. As a result, damage to the shutter curtain can be prevented in the same manner as described above.

Furthermore, it is more accurate than the example shown in FIG. 8 in which time is measured without being affected by dirt on the film FI, and the film is not exposed unnecessarily.

Although the above description has been made using a camera that feeds film through a thrust operation, the present invention can also be applied to a camera that uses a normal cartridge in which the film reader section is exposed to the outside, or a camera that does not perform a thrust operation at all. Applicable. In this case, since there is no risk of damaging the shutter curtain when loading the cartridge, it is sufficient to perform the above control only when rewinding by one rewind.

Also, after loading the cartridge, the entire film is wound onto the winding spool, and then it is rewound one frame at a time after each shooting.
The present invention can also be applied to a type of camera that performs so-called pre-winding.

G0 Effects of the Invention According to the present invention, the shutter curtain is kept open at least while the leading edge of the film passes immediately after the aperture when the film is fed, so that the shutter curtain is kept open during the thrust operation and the rewind operation. There is no possibility that the leading edge of the film may damage the shutter curtain.

[Brief explanation of the drawing]

1 to 7 show an embodiment of the present invention, and FIG.
) is a perspective view schematically showing the film feeding mechanism of the camera according to the present invention, FIG. 1(b) is a block diagram of the control system, FIG. 2 is a perspective view of the camera seen from the rear, and FIG. 4 and 5 are flowcharts of the processing procedure, and FIGS. 6 and 7 are diagrams illustrating the film feeding state. FIGS. 8 and 9 are flowcharts showing different embodiments, and FIGS. 10(a) and 10(b) are diagrams explaining still another embodiment. 10: Film cartridge 21 Ni last and rewind motor

Claims (1)

[Claims] A shutter that opens and closes a shutter curtain just before the aperture, and a feeding means that feeds the film between the cartridge and the take-up spool, and when the film is fed, the film moves right after the aperture. Shutter curtain protection for a camera, characterized in that the camera is provided with a shutter control means for keeping the shutter open at least while the leading edge of the film passes immediately behind the aperture during the film feeding. Device.